Farrowing and Weaning Pigs in Deep Straw
In May 2003, West Central Research and Outreach Center (WCROC), University of Minnesota, completed a new housing system for sows and piglets. Formerly a dark, smelly structure for housing pigs over a liquid manure pit, the newly remodeled building underwent a remarkable transformation. Modeled on a Swedish system, it houses pigs in amply lit rooms, amidst an abundance of straw, with plenty of room to roam, socialize, root, and give birth to their young. AWI's Farm Animal Economic Advisor Marlene Halverson contributed to the design.
The 45 foot by 120 foot building is divided into four spacious rooms. Each of three rooms houses eight sows and their piglets, while one room houses gilts (young female pigs) "recruited" from the WCROC pig herd to become breeding sows. At one end of each room, "garage" type doors permit easy cleaning and rebedding with a small tractor.
Individual feeding stalls and a deep straw bed in the gilts' room mimic the layout of the Center's gestation hoop (see Winter 2004 AWI Quarterly). Gilts gain experience living in groups and using feeding stalls before joining the main sow herd. Fresh straw added daily provides material for occupation and is consumed by the gilts between meals.
In the farrowing (birthing) rooms, staff set up eight portable farrowing pens, four along each sidewall, with pen entrances facing a spacious area in the middle. They bed each pen with straw. Sows are brought into the rooms a few days before they are due. Soon after, each sow chooses a pen in which she arranges a nest and gives birth. The seven foot by ten foot pens are roomy enough that sows can enter, lie down to nurse, rise, and leave again with a low incidence of injuring piglets. When all piglets can climb out of the pens, the pens are dismantled and removed so piglets and sows can mingle freely.
Sows naturally begin to wean piglets by reducing the number of nursings they initiate. Because feed is continuously available in the farrowing rooms, piglets learn to eat by their mothers' sides. Their digestive systems become accustomed to solid feed. Staff complete the weaning process when piglets are five to six weeks old by taking sows to the gestation hoop for rebreeding. Sows' scents are left behind in the beds, reducing piglets' stress associated with their "loss." A five to six week nursing period allows young pigs' immune systems to develop. Reducing the stress of weaning helped Swedish pig farmers adjust to Sweden's legal prohibition on subtherapeutic antibiotic use. By contrast, industrial production entails weaning piglets abruptly at one to three weeks of age.
WCROC is pleased with the system. Sows farrowing in October 2003 weaned an average of 10.5 pigs per sow. Because the Center remodeled an existing building rather than building new to Swedish specifications, getting the ventilation system to work properly has been a challenge as has learning to manage deep straw beds, but workers are adjusting. If successful, the remodeling can provide an example for farmers who have buildings they would like to convert. The systems elicited favorable responses from farmers attending a November 2003 "open house." AWI applauds this progressive research to improve pig welfare.